In the field of traffic roadway building or repairing, a method is known for adding cut fibers in a binder allowing to structure the binder layer so as to withstand tearing due to the traffic or to transversal stresses or to restrict cracking propagations. Such a method comprises nearly simultaneously spreading in the forwarding direction of a spreading system, a binder layer followed by a cut fiber layer, in turn coated with a second binder layer. Such an operation is generally followed by coating such layers with mineral or naturally occurring or synthetic granulates in order to allow for the traffic to run. The binder is generally a bitumen emulsion.
Such systems comprise continuous fiber-cutting bars provided with cutters in a number different from the number of bitumen emulsion spreading sprays which does not allow the supplying or spreading width to be varied without risking to compromise the performance of the method.
Such existing spreading systems do not allow for a reliably transversally dispensing fibers, a necessary requirement for the feasability and durability of such methods.
As to the flow rates, the existing systems allow for mean flow rates of 60 grammes/m2 of cut fibers and, more preferably, of 90 grammes/m2 of cut fibers at the most because of the technology being used. In addition, the cutter rotative speed, beyond a certain limit, make them inoperative as fibers curl about the cutters without being nevertheless cut, making the maintenance difficult all the more as this requires the full dismantling of the fiber cutting set, handling heavy and bulky mechanical parts, sometimes hazardous for the operator. This physical limitation of the cutting speed makes it impossible to increase the fiber flow rate through increasing the cutting tool speed.